Arthroscopic Anterior Cruciate Ligament Reconstruction with a Hamstring Autograft

Abstract

Polven eturistisiteen (ACL) katkeaminen on vakava polven ligamenttivamma, joka yleensä johtaa toistuviin polven alta pettämisoireisiin, turvotteluun ja kipuiluun. Hoitona on rekonstruktio käyttäen esim. potilaan omia Hamstring-jänteitä tai patellajänteen keskikolmannesta siirteenä. Tämän tutkimuksen tarkoituksena oli tutkia kliinisiä paranemistuloksia tähystysleikkauksessa tehdyn eturistisiteen rekonstruktion jälkeen. Myös siirteen paikan, lihasvoimien sekä polven leikkaushetkisen kunnon yhteys paranemistuloksiin selvitettiin. Lisäksi kartoitettiin leikkauksenjälkeisen nivelrikon esiintyvyys sekä siihen liittyviä tekijöitä. Prospektiivisessa randomoidussa tutkimuksessa verrattiin uutta eturistisiteen tuplasiirretekniikkaa perinteisesti käytettyyn yhden siirteen tekniikkaan. Magneettitutkimuksella arvioitiin biosulavien ruuvien ja metalliruuvikiinnityksen eroja paranemistuloksissa.

Yhteenvetona tästä tutkimuskokonaisuudesta voitiin todeta, että ACL-rekonstruktiopotilailla on lihasvoimavajauksia vielä 6 vuotta leikkauksen jälkeen, joskin voimavajaukset näyttävät pienenevän ajan myötä. Yhden siirteen leikkaustekniikkaa käytettäessä sekä femoraalisen että tibiaalisen siirteen paikan yhtäaikainen arviointitulos korreloi sekä etu-takasuuntaisen että kiertosuuntaisen polven tukevuuden kanssa. Polvissa joissa oli kierukkavamma ACL-korjausleikkauksen aikaan, on odotettavissa enemmän polven kulumamuutoksia.

Eturistisiteen rekonstruktion uusi tuplasiirretekniikka näyttää johtavan parempaan polven kiertosuuntaiseen tukevuuteen kuin yhden siirteen leikkaustekniikka. Se näyttää suojaavan polvea myös uusintavamman aiheuttamalta siirteen pettämiseltä. Biosulavien ruuvien käyttö yhden siirteen tekniikassa johtaa suurempaan femoraalisen tunnelin laajenemiseen kuin metalliruuvien käyttö, sekä useammin siirteen pettämiseen.

The objective of this thesis was to evaluate the clinical outcome of the anterior cruciate ligament (ACL) reconstruction with a hamstring autograft. The associations of the graft placement, muscle strength, and the condition of the knee at the time of the operation with the clinical outcome were studied. Also, the prevalence of osteoarthritis in mid-term and the factors associated with it were characterized. In addition, in a prospective, randomized study, a novel double-bundle reconstruction technique was compared to a conventional technique, and magnetic resonance imaging (MRI) was used to evaluate the outcome of bioabsorbable versus metal screw fixation.

Patients clinical assessment included evaluation of the anteroposterior and rotational knee stability, and the knee scoring system of the International Knee Documentation Committee (IKDC). The anteroposterior stability testing was done with a KT-1000-arthrometer. The subjective-functional assessment of the knee was done by a Lysholm knee score, and patients activity level was evaluated using the Tegner score. The functional performance of the knee was evaluated using the one-leg-hop -test, and muscle strengths of the lower extremities were measured by Dynacom testing apparatus. The radiographic knee assessment of the osteoarthritic changes and ACL-graft placement was done. MRI was used to study the extent of graft-tunnel widening, absorption of the bioabsorbable screws, and possible adverse tissue reactions.

The study I showed that the muscle strength deficits at the injured lower extremity persisted even 3 to 7 years after the ACL reconstruction. However, they seemed to recover with time, especially the quadriceps strength of the patients with a bone-patellar tendon-bone (BTB) autograft. This suggested that in BTB patients the quadriceps strength was lower postoperatively compared to those treated with a hamstring autograft. The knee flexion (hamstring), and knee extension (quadriceps) strength deficits were associated with the subjective Lysholm score indicating that the smaller the strength difference between the operated and the non-operated limb, the less the patient experienced symptoms in the knee. Also, the knees with no instability had less flexion torque deficit than the knees with nearly normal or abnormal stability.

The study II revealed a correlation between the femoral graft position and the Lysholm score, so that the more posterior the graft was placed, the higher was the score. Simultaneous evaluation of the femoral and tibial graft placements proved useful by predicting both the anteroposterior and rotational stability of the knee.

The study III showed that meniscectomy at the time of the ACL reconstruction resulted in more severe osteoarthritic changes in the knee than reconstruction without meniscectomy. Also, the Lysholm score was higher when meniscectomy was not done. The prospective, randomized study IV comparing a novel double-bundle ACL-reconstruction technique to a conventional single-bundle technique indicated that the new technique resulted in better rotational stability of the knee and was able to protect the patients from a reinjury-induced graft failure. No between-groups difference was noted in the occurrence of complications, or IKDC or Lysholm scores.

The study V showed that postoperative femoral tunnel widening was larger with the bioabsorbable screws than metal screws, as judged with the MRI 2-years postoperatively. In the tibia, no difference was noted. The use of bioabsorbable screws resulted in more graft failures compared to the use of metal screws. After excluding the graft failures, the clinical outcome of the patients was equally good in the two groups. The follow-up tibial tunnel diameter correlated with the stability. In conclusion, the studies I-V of this thesis showed that muscle strength deficits in the injured extremity 6 years after the ACL reconstruction were associated with inferior clinical outcome of the patient. However, the muscular performance seemed to improve by time, also in long-term. The graft placements (as assessed by simultaneous evaluation of the femoral and tibial graft placements) had an effect on both anteroposterior and rotational knee stability so that optimal graft positioning improved the stability. More severe osteoarthritic changes could be expected in the knees showing accompanying meniscal injury at the time of the reconstruction. A new double-bundle ACL reconstruction technique resulted in better rotational stability of the knee than the conventional single-bundle technique, and, it seemed to protect the knee from reinjury-induced graft failures. Finally, the use of bioabsorbable screws with the single-bundle technique resulted in larger femoral tunnel widening than the use of metal screws, and more graft failures.